Periodic Reporting for period 1 - miROMeS (miRNA biomarkers of Osseous Metastases in Serum from breast cancer patients)
Berichtszeitraum: 2015-06-01 bis 2017-05-31
Circulating breast tumor cells that escape the primary tumor and invade the bone marrow express sets of deregulated genes and microRNAs (miRNAs) that facilitate their bone tropism and enhance engraftment of disseminated tumor cell in bone marrow which may subsequently induce osteolytic lesions. Indeed, transcriptional profiling of primary tumors has revealed gene and miRNA signatures that correlate with metastatic bone relapse in patients. Insight into the molecular mechanisms of cancer cell dissemination to bone has been obtained through associations between miRNA expression in primary tumor and metastasis with the involvement of specifically cognate genes during bone metastasis formation. MiRNAs are short and single-stranded RNAs that repress gene expression and that have been suggested as biomarkers of bone disease, driven by their remarkable stability and accessibility in blood and by the property of circulating miRNAs as a reflect of tumor miRNAs.
In this, the utility of miRNAs as biomarkers of bone disease has been studied in the present research that has combined the expertise from the ERS in miRNA biomarker analysis and the host laboratory’s expertise in bone metastasis for the following objectives:
(i)- To identify genes and miRNAs in breast primary tumors the deregulation of which is associated to bone metastasis occurrence.
(ii)- To identify serum miRNA signatures of bone metastasis in breast cancer patients with bone metastasis compared to patients without bone metastasis.
(iii)- To evaluate the predictive value of candidate miRNA biomarkers in a focused miRNA panel using serum from patients with long-term follow-up data
We have also shown that estrogen related receptor alpha (ERRα) expression is higher in castration-resistant prostate cancer patients with bone metastases than without, and that ERRα in prostate cancer alters molecular signaling in the stroma via the regulation of periostin and TGF expression in bone metastases and in primary tumor.
Finally, we have provided novel evidence that miR-30 family members (miR-30a, miR-30b, miR-30c, miR-30d and miR-30e) act as bone metastasis suppressor genes in breast cancer, inhibiting tumor cell invasion, osteomimicry and bone destruction. We identified a number of genes associated with osteoclastogenesis stimulation (IL-8, IL-11), osteoblastogenesis inhibition (DKK-1), tumor cell osteomimicry (RUNX2, CDH11) and invasiveness (CTGF, ITGA5, ITGB3) that were direct and/or indirect targets for repression by miR-30s. Among these genes, integrin ITGA5 was a previously unknown miR-30 target. By silencing ITGA5 in breast cancer cells, colonization of the bone marrow by tumor cells was drastically reduced in vivo. Overall, our data indicate that miR-30s employ multiple mechanisms to impede breast cancer bone metastasis. These findings may pave the way to a new field of therapeutic interventions in breast cancer patients with bone metastasis.
Each column represents 1 patient (3 patients per groups). Yellow box indicates miRNAs that were significantly differently expressed (t-test, p<0.05).
As regard to luminal breast cancer, statistical analyses identified 58 miRNAs that were differently expressed in serum from patients with bone and visceral metastasis compared to serum from patients with no metastasis. Bioinformatic analysis was conducted on these miRNAs to select a miRNA data set. The miRNAs will be validated by a custom-designed focus panel in the test phase and in the validation phase, using the serum of 40 women with early breast cancer from the Adjuvant Zoledronic Acid to Reduce Recurrence (AZURE) trial who subsequently relapsed at skeletal sites only, visceral sites only or did not relapse at 10+ years follow up. --> See figure 2 attached
As regard to triple negative breast cancer, statistical analysis identified 12 miRNAs that were differently expressed in serum from patients with no metastasis compared to patients with bone or lung metastasis. To establish a miRNA data set that can be used in the test phase and in the validation phase in a cohort, we analyzed samples arising from a patient-derived xenograft model (PDX) that retain the histological and genetic characteristics of the original triple-negative tumor. --> See figure 3